1. Field of the Invention
The present invention relates to an engine starting device in a vehicle structured such that a rotation of a crankshaft of an engine is shifted by a V-belt type continuously variable transmission so as to be transmitted to a driving wheel, such as a scooter type vehicle or a small all terrain vehicle.
2. Related Art
In this kind of starting device, as described in Japanese Patent Application Laid-Open Publication No. 62-48960 and Japanese Patent Publication No. 3518709, a starter driven gear is integrally formed in an outer peripheral portion of a drive V-pulley of the V-belt type continuously variable transmission integrally provided in the crankshaft of the engine. In addition, a starter drive gear driven by a human power or a starter motor is arranged near the drive V-pulley. At a time of starting the engine, a starter driven gear is rotationally driven by the starter drive gear, so that an engine is started by run-up rotating the crankshaft.
As described in the prior art publications mentioned above, in the conventional starting device, an outer diameter of the drive V-pulley is set sufficiently large so as to prevent a tooth shape of the starter driven gear formed in the outer peripheral portion of the drive V-pulley from lapping over a belt sliding contact surface. Further, because if the tooth shape of the starter driven gear laps over the belt sliding contact surface of the drive V-pulley, a side surface of the V-belt tends to wear and a durability of the V-belt is significantly lowered.
However, if the outer diameter of the drive V-pulley is made sufficiently large as mentioned above, a size of an engine case (a crankcase) in which the V-belt type continuously variable transmission is accommodated is enlarged and compactness is deteriorated, thus being inconvenient. Furthermore, if the outer diameter of the drive V-pulley is enlarged, a tooth number of the starter driven gear is necessarily increased, and it is necessary to reduce the tooth number of the starter drive gear at that degree.
Accordingly, it is difficult to obtain a proper starter gear ratio, and there is a tendency that it is hard to start the engine particularly in a recoil type starting device in which an engine start is executed by pulling a rope by a hand so as to rotate a starter drive gear.